In February, a liberal activist named Curtis Morrison secretly recorded McConnell and re-election campaign staffers talking about tactics they would use against actress Ashley Judd, should she challenge McConnell in next year’s election. Judd later said she wouldn’t run for Senate, but Morrison gave the recordings to Mother Jones, a liberal political magazine that published the audio and transcripts at its website.

McConnell has demanded anyone involved in the secret recordings be prosecuted.

Politico reports that any attempts to subpoena evidence from Morrison would probably need the approval of U.S. Attorney General Eric Holder, who has to sign off on any such subpoenas for journalists. Morrison has worked as a paid freelancer for a Louisville-based online news outlet, in addition to his work with political groups that have said their goal is to defeat McConnell in 2014.